The invention relates to the use of the alkane diols as foam controlling agents.
Foam control or elimination in many waterborne applications and industrial processes is critical for obtaining optimal performance in application and high process efficiency. The importance of foam control and elimination in applications such as waterborne coatings, inks, adhesives, and agricultural formulations and in industrial processes such as oil well pumping, petroleum gas scrubbing, cleansing and disinfecting, food processing, pulp and paper processing, fermentation, metal treatment, polymer and chemical synthesis, waste-water treatment and textile dying and finishing is well-appreciated in the art.
Foam controlling agents are widely used in polymer production and processing, as foam can lead to reduced production capacity, efficiency and equipment problems. In particular, severe foaming problems commonly result upon stripping unreacted monomers from the polymer product.
Undesirable foam can lead to inefficient mixing, poor productivity, reduced vessel capacity and equipment failure in many common industrial processes. For instance, foaming in refinery processes such as drilling, production, stimulation, distillation, extraction, gas and liquid scrubbing and other operations leads to a number of operating difficulties and significant economic consequences. In acid gas sweetening, gases such as carbon dioxide and hydrogen sulfide are removed via scrubbing with an aqueous amine solution. Problematic foam can occur during both the scrubbing or regeneration steps in this process.
For applications such as coatings, the dynamic nature of spraying, rolling, or brushing the coating onto a substrate will introduce air into the system which can manifest itself as foam. This foam can cause coating failure due to factors such as low gloss or poor surface coverage. In cleaning applications, a small amount of controlled foam may be needed during cleaning, but too much foam can affect the perceived time to clean and rinse the soiled article. Defoamers and antifoams are additives that are used to reduce or eliminate problematic foam. The term xe2x80x9cantifoamxe2x80x9d refers to a long-acting additive that prevents foam formation. The term xe2x80x9cdefoamerxe2x80x9d refers to an additive that eliminates, or at least reduces, existing foam. The term xe2x80x9cfoam controlling agentxe2x80x9d, as used herein, refers to an additive that prevents and/or eliminates/reduces foam since many applications and processes require both foam prevention and foam elimination.
In many applications, it is desirable for foam controlling agents should impart positive ancillary surface properties, such as wetting, dispersion, emulsification, solubilization, flow and leveling, adhesion, and gloss. For example, defoamers and antifoams that act as wetting agents will greatly reduce surface defects in coatings, inks, adhesives and agricultural formulations. In addition, such multi-functional materials will allow for the reduction or elimination of wetting agents in a waterborne composition, thereby reducing the total amount of additives. The ability of a material to act as a wetting agent in waterborne formulations is determined by its ability to reduce the surface tension of water. Equilibrium surface tension performance is important when a system is at rest. However, the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are utilized. Such applications include the spraying, rolling and brushing of coatings, adhesives or agricultural formulations, or high-speed gravure or ink-jet printing. Dynamic surface tension is a fundamental quantity which provides a measure of the ability of a substance to reduce surface tension and provide wetting under high-speed application conditions. Also, it is under such high speed application conditions where the entrainment of air and the creation of foam is a problem.
In order to achieve wetting, additives such as dioctyl sodium sulfosuccinate (DOSS) are often employed. An adverse effect that often accompanies its use is a large amount of foam, which may cause a need for the use of a second additive as a defoamer to control that foam. Thus, the ability of a single agent to impart superior foam control and to strongly influence other performance attributes such as wetting, flow and leveling, corrosion inhibition, emulsification, adhesion, gloss, and/or dispersion is highly valued in application areas such as coatings, inks, adhesives, cleaning, semiconductor, dye, or pigment manufacture, metalworking and finishing, agricultural formulations, pulp and paper, oil and gas applications, chemical, emulsion, and pharmaceutical manufacturing, food and beverage processing, wastewater treatment, and textile manufacturing and processing.
Alkane diols such as ethylene or propylene glycol are most commonly known as solvents in areas such as coatings, inks, and adhesives formulations. Although their addition to formulations is sometimes for the purpose of reducing solid levels, providing freeze-thaw benefits, or (at higher use levels) to enhance wetting, they have not been reported as multi-functional foam controlling agents.
U.S. Pat. No. 2,992,278 describes a process for the production of 1,4-saturated diols. J. Org. Chem., 1962, 27, 2398 further elaborates on the hydrogenation and hydrogenolysis of symmetrically substituted 1,4-acetylenic glycols. Neither discusses the performance of these products.
2,4,7,9-tetramethyldecane-4,7-diol (HTMDD) has been reported in IandEC Product Research and Development, 1965, 4, 236 as a wetting agent, albeit one with inferior wetting properties relative to its acetylenic analogue, 2,4,7,9-tetramethyldecyne-4,7-diol (TMDD). Although foam control data is reported for various ethoxylated derivatives of HTMDD, no foam control information is reported for HTMDD itself.
GB 843,379 describes acetylenic diols and alkane diols as compatible solubilizers, which when used in conjunction with sulfonate surfactants, impart foam stability to a shampoo composition. Specifically disclosed are shampoo compositions containing 3,6-dimethyl-4-octyne-3,6-diol (DMOD or Surfynol(copyright) 82), 2,5-dimethyl-3-hexyne-2,5-diol (DMHD or DH), or 3,6-dimethyloctane-3,6-diol (HDMOD) in amounts from 6-50% by weight, with 8-20% by weight of a surfactant, and from 6-50% by weight of an alkylolamide of a fatty acid. These formulations are said to impart a large volume of foam of good stability. Since this combination of products is said to be effective in these performance attributes because of the combination of components contained within the formulation, the alkane diol, HDMOD, is actually adding to the foam, not controlling or reducing it.
U.S. Pat. No. 4,287,080 describes improved detergent compositions. An integral part of these compositions is a component which, in its broadest description, is 0.5-50% of a tertiary alcohol having at least 5 carbon atoms and less than 100 carbon atoms per molecule. Numerous tertiary alcohols are described with no mention of any performance differences among such examples as 1-methylcyclohexanol, 2-methyl-2-propanol, and 2,5-dimethyl-2,5-hexanediol (HDMHD).
U.S. Pat. No. 4,692,277 discloses C8-C12 diols that are included as components in a hard surface liquid cleaner with no mention of their foaming performance.
U.S. Pat. No. 5,808,110, U.S. Pat. No. 3,330,871, and WO Pat. 93/18431 discuss the use of alkane diols as safety solvents or as additives for liquid crystals. None of these disclosures mention their use as foam controlling agents or as wetting or flow and leveling agents for coating, ink, and adhesive applications.
The present invention pertains to a method for controlling the foaming of a waterborne composition or an industrial process by the incorporation of a foam controlling agent. The method comprises utilizing as the foam controlling agent a compound of the formula:
HOR1R3Cxe2x80x94[CH2]nxe2x80x94CR2R4OH
R1 and R2 are independently selected from the group of alkyl radicals having from 3 to 6 carbon atoms. R3 and R4 are independently alkyl radicals having from 1 to 2 carbon atoms. n is an integer from 1 to 6. The compound generates an initial (t=0 min.) or a final (t=10 min.) foamed density at least 30% greater than that of a 0.5 wt % aqueous solution of a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12) when added at 0.2 wt % to the C12-C15E12 solution.
The present invention also pertains to an aqueous composition comprising a foam controlling agent, which composition manifests greater foaming in the absence of the foam controlling agent. The foam controlling agent is an alkane diol present in a foam controlling amount and having the formula:
HOR1R3Cxe2x80x94[CH2]nxe2x80x94CR2R4OH
R1 and R2 are independently selected from the group of alkyl radicals having from 3 to 6 carbon atoms. R3 and R4 are independently alkyl radicals having from 1 to 2 carbon atoms. n is an integer from 1 to 6. The compound generates an initial (t=0 min.) or a final (t=10 min.) foamed density at least 30% greater than that of a 0.5 wt % aqueous solution of a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12) when added at 0.2 wt % to the C12-C15E12 solution.
This invention relates to the use of alkane diols as foam controlling agents. In many cases, these alkane diols provide other performance benefits such as enhanced wetting, gloss, adhesion, and/or leveling. The excellent defoaming and antifoaming properties of these foam controlling agents suggest that these materials are likely to find applicability in applications and processes in which the reduction, prevention or knock-down of foam are important. Such applications include protective and decorative coatings, inks, adhesives, agricultural formulations, oil well pumping, petroleum gas scrubbing, cleansing and disinfecting, food processing, pulp and paper processing, fermentation, metal treatment, polymer and chemical synthesis, waste-water treatment, and textile dyeing and finishing. In addition, these materials have the ability to also reduce the dynamic surface tension of waterborne compositions. Such a combination of performance attributes allow these materials to be used to control and eliminate foam with significantly less deleterious effects in application, making them extremely useful in coatings, inks and adhesives. Moreover, the wetting ability of these foam controlling agents will allow these materials to be utilized in polymer production and processing without the appearance of negative defects in downstream applications.
The ability of an additive to reduce foam is of great importance to the performance of water-based coatings, inks, fountain solutions, adhesives, metalworking fluids, agricultural formulations, and electronic chemicals. Lower foam in a system means that higher throughputs are possible in manufacturing and better performance of the formulation or product as it is used. Foam control agents that offer more than just one performance benefit are highly regarded and often considered of great economic benefit. Additionally, having such a product as a liquid which does not contribute a significant amount of volatile organic compounds (VOCs) to the total formulation is of benefit. The alkane diols described herein fulfill these performance benefits.
The alkane diols of this invention expand the range of multifunctional foam control agents to those which not only have defoaming and antifoaming performance, but which impart a unique combination of enhanced wetting, leveling, and gloss, low defects and other positive aesthetic properties. Additionally, the use of these surfactants is possible in a multitude of waterborne compositions including coatings, inks, adhesives, fountain solutions, agricultural formulations, metalworking fluids, and electronic chemicals.
The term xe2x80x9cwater-basedxe2x80x9d, xe2x80x9cwaterbornexe2x80x9d, xe2x80x9caqueousxe2x80x9d, or xe2x80x9caqueous mediumxe2x80x9d, as used herein, means a solvent or liquid dispersing medium which comprises water, preferably at least 90 wt %, and most preferably at least 95 wt %, water. Obviously, an all water medium is also included.
In another embodiment of the invention, the foam controlling agents may be used as wetting agents to improve upon, among other attributes, the minimization of defects, leveling performance, gloss, and stain resistance.
There are significant advantages associated with the use of these alkane diols as multifunctional foam controlling agents in waterborne compositions such as coatings, inks, adhesives, fountain solutions, agricultural formulations, electronic chemicals formulations, and cleaning formulations, as well as processing aids for areas such as metalworking and finishing, oil and gas processing, pulp and paper processing, wastewater treatment, and dye, pigment, textile, emulsion, chemical, and pharmaceutical manufacturing. These benefits include, but are not limited to: foam controlling agents which have low odor and color; foam controlling agents which comprise 100% active ingredients, thus not requiring carrier solvents, fluids or other additives; foam controlling agents capable of reducing the dynamic surface tension of waterborne coatings, inks, adhesives, agricultural, and cleaning formulations such that even contaminated surfaces are highly wetted; the reduction of coating or printing defects which are normally associated with conventional foam controlling agents; an improvement in the wetting performance of a waterborne system or process operated at high speeds; waterborne coatings, inks, and adhesives which have low volatile organic content, rendering the formulation environmentally favorable.
As set out above, the present invention provides a method for controlling the foaming of a waterborne composition or an industrial process by the incorporation of a foam controlling agent. The method comprises utilizing as the foam controlling agent a compound of the formula:
HOR1R3Cxe2x80x94[CH2]nxe2x80x94CR2R4OH
R1 and R2 are independently selected from the group of alkyl radicals having from 3 to 6 carbon atoms, preferably from 4 to 6 carbon atoms, and more preferably from 4 to 5 carbon atoms.
R3 and R4 are independently alkyl radicals having from 1 to 2 carbon atoms, preferably R3 and R4 are methyl radicals.
n is an integer ranging from 1 to 6, preferably from 1 to 4, more preferably from 1 to 3, and most preferably 2.
In a preferred embodiment, R1 and R2 are independently selected from the group of alkyl radicals having from 4 to 6 carbon atoms, R3 and R4 are methyl, and n is 2. In another preferred embodiment, the compound is 2,4,7,9-tetramethyldecane-4,7-diol. In yet another preferred embodiment, the compound is 2,5,8,11-tetramethyldodecane-5,8-diol.
The foam controlling agent generates an initial (t=0 min.) or a final (t=10 min.) foamed density at least 30% greater than that of a 0.5 wt % aqueous solution of a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12) when added at 0.2 wt % to the C12-C15E12 solution. Preferably, the compound generates an initial or a final foamed density at least 40% greater than that of a 0.5 wt % aqueous solution of a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12) when added at 0.2 wt % to the C12-C15E12 solution, and most preferably at least 50% greater. Preferably, the foam controlling agent generates an initial (t=0 min.) and a final (t=10 min.) foamed density at least 30% greater than that of a 0.5 wt % aqueous solution of a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12) when added at 0.2 wt % to the C12-C15E12 solution. Preferably, the compound generates an initial and a final foamed density at least 40% greater than that of a 0.5 wt % aqueous solution of a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12) when added at 0.2 wt % to the C12-C15E12 solution, and most preferably at least 50% greater. The primary alcohol ethoxylate (PAE) test employed here, also known as the Blender Foam Test, is described in Am. Soc. For Testing Materials, Method D3519-88, Philadelphia, Pa., 1953, which disclosure is incorporated herein by reference. The primary alcohol ethoxylate employed in this test is Neodol(trademark) 25-12, a 12 mole ethoxylate of a C12-C15 primary alcohol (C12-C15E12).
The alkane diols are suitable for use in an aqueous composition comprising in water an inorganic compound which is a mineral ore or a pigment or an organic compound which is a pigment, a polymerizable monomer, an emulsion which is an aqueous suspension of the addition or condensation polymers of a vinyl monomer, an oligomeric resin, a polymeric resin, a detergent, a caustic cleaning agent, an herbicide, a fungicide, an insecticide, or a plant growth modifying agent.
Foam control may be measured through various test methods, all of which involve agitation or movement of a liquid so as to entrain air into the system, with the subsequent breaking of that entrained air which usually manifests itself on the surface or in the liquid as foam. A measure of the antifoaming ability of an agent is recorded as the initial foamed height, volume, or density of the system. The defoaming ability of an agent is shown by the time required to break the foam either partially or completely. Although a standard test for measuring the foam performance of a defoamer by itself (Example 6) is the Ross-Miles foam test (Am. Soc. For Testing Materials, Method D1173-53, Philadelphia, Pa., 1953), variations of the Blender Foam Test described in Am. Soc. For Testing Materials, Method D3519-88, Philadelphia, Pa., 1953, are more commonly used in systems with more than one component, as described in Examples 1-5 and 7, and is incorporated herein for reference. Since the application areas referred to in examples 1-5 and 7 have different foam control needs, the method of agitation in our studies are varied (Red Devil Shaker for example 2, Dispermat for examples 3 and 4, and Waring Blender for examples 1-5 and 7), but the comparisons for examples 1-5 and 7 are all made in terms of the weight of the sample divided by the volume of the foam and liquid, hereafter referred to as the xe2x80x9cfoamed densityxe2x80x9d. Although the Blender Foam Test method calls for a final measurement at 5 minutes, we have measured the foamed density at time intervals which are significant for each application area. The significance of foam control may vary from one application area to another, but an important component of this invention is that regardless of the type of agitation, the alkane diol agents of interest are effective foam controlling agents in multicomponent systems.
Another benefit that a multifunctional foam controlling agent may have begins with, but is not limited to, wetting. The Maximum Bubble Pressure method of measuring dynamic surface tension is described in Langmuir, 1986, 2, 428-432 and is incorporated herein for reference. The surface tension reduction necessary for a given system is highly dependent upon the surfaces which need to be covered or wetted in that application.
The amount of alkane diol that is effective to reduce or eliminate the foam of a water-based, organic compound containing composition may range from 0.001 to 20 wt %, preferably from 0.001 to 10 wt %, and most preferably from 0.001 to 5 wt %, based on total weight of the formulation. The most favorable amount will vary from one application to another, depending upon the foam contributing species in that system.
A typical water-based decorative or protective coating formulation to which foam controlling agents of the invention may be added would comprise the following components in an aqueous medium at 30-80% solids:
A typical water-based ink composition to which the foam controlling agent of the invention may be added would comprise the following components in an aqueous medium at 20 to 60% solids:
A typical water-based agricultural composition to which the foam controlling agent of the invention may be added would comprise the following components in an aqueous medium at 0.2 to 80% solids:
A typical fountain solution composition for planographic printing to which the foam controlling agent of the invention may be added would comprise the following components:
A typical metalworking fluid to which the foam controlling agent of the invention may be added would comprise the following components:
A typical hard surface cleaner to which the foam controlling agent of the invention may be added would comprise the following components:
A typical water-based photoresist developer or electronic cleaning composition to which the foam controlling agent of the invention may be added would comprise the following components:
A typical pressure overprint varnish to which the foam controlling agent of the invention may be added would comprise the following components: